I think the original USB from Sony is still in the box somewhere as I've used another one that was already attached to a port in the back of the machine and threaded forward. Worked like a charm for the last however many months.

It's a standard 5-pin mini usb cable. If you do a little googling, you can find versions that also have a plug that works to charge the device from USB, intended for the PSP. Here's the one I found on Amazon, works like a dream and only cost $2.50:http://www.amazon.com/Insten-2-1-Dow...dp/B000F1TNCA/

Handy to have the power plug to charge your reader from a usb wall plug, or charge from the computer without going into data transfer mode.

Now THAT'S a handy cable! Best of both worlds. I have a wall wort charger which you can use to charge USB devices with a cable, but it doesn't charge my Reader with a standard-to-mini USB cable. That cable allows use of the PSP charging port on the Reader from a USB connection, bypassing the transfer mode issues. I want one.

It's a mystery as to why the USB Mini B connector refuses to charge on most non-PC USB power supplies, but will occasionally find one that it likes. It also refuses to charge on a few PC USB ports.

That sounds like either the PRS unit is too picky about voltages on the USB cable, or (more likely) the USB port / wart doesn't put out enough amperage.

I see this all the time with little USB 2.5" external drives. Some USB ports work, some don't. Depending on whether the hard drive inside the USB enclosure is close to the amperage limit for the USB spec.